side action parting line question 2

[loughnane]

Is it possible to create the part shown using a side action where the highlighted red line is the witness line left from the side action?

The purpose is to avoid having the parting line be at the extents of the face.

(obviously not the real part, but it's representative enough)

Chris Loughnane - Product Design

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[patprimmer]

Yes

You have a retracting pin with a shoulder on it.

ie if it's a 1" hole you use a 2" pin and turn the end down to desired hole size, corrected for shrinkage of course.

Regards
Pat
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[loughnane]

So I would imagine that this would have to be, like you say, a retracted pin and wouldn't be able to achieved via use of a cam like this...

http://www.ferris.edu/htmls/academics/course.offerings/hillm/MYWEB7/Action/SLIDE/Slide-Basic.htm

Thanks for the quick response, now I just need to wait for china to tell me it's impossible.

Chris Loughnane - Product Design

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[patprimmer]

I would not call that a cam. I would call it an angles pin or horn and a sliding block. Any toolmaker even in China who can't do that should not be trading.

As these questions are real basic, dare I say student level, it seems you need to invest in at least an elementary book on mould design and mould making. I am sure the Society of Plastics Engineers can provide a suitable list to choose from.

Regards
Pat
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[loughnane]

Apologies for my less-than-guru nomenclature. I've seen people refer to it as a cam-pin interface... is there a more technically correct term I should be using?.

I've designed parts this way before. The impetus for this post was not that I can't design a part with a side action, but that I am in the unfamiliar position of having a molder question something so basic. I design parts instead of molds, so I was looking for some good honest feedback on how to explain the tool I was envisioning to the molder. It's my bad for not writing a very articulate post... I was in a bit of a hurry.

In any case, I did find a really good reference (below). Solidly answered my question and then some. They discuss options for moving the witness line off of the primary parting line, such as for submerging the cam/pin interface in the mold or skipping the cam/pin action all together and going with a modular core compression system.

http://www.pfa-inc.com/msa_how_why_when.pdf

and part II

http://www.pfa-inc.com/apps_rule_actions.pdf

If anyone has a particular favorite book full of the kind of information in the PDFs above, I would definitely snatch that up.


Chris Loughnane - Product Design

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[MikeHalloran]

>>>The impetus for this post was not that I can't design a part with a side action, but that I am in the unfamiliar position of having a molder question something so basic.<<<

... This suggests that you are dealing with a faux molder or an unskilled intermediary.


Be careful.



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

I agree with Mike.

A sliding side core with angled pins is really elementary and for any real moulder to question its validity is beyond belief. I have heard the pins called pins and horns at different times.

Terminology varies, but it certainly is not a cam. A cam involves some sort of ecentric profile to lift by turning the shaft it is on.

http://en.wikipedia.org/wiki/Cam

The major old school high profile raw materials suppliers will all have some data on toolmaking.

Ticona, DuPont, BASF, Bayer, DSM, Sabic and whatever Elf Atochem call themselves this week are a few that spring to mind.

I am going from memory, but Mengens? and Mohren? springs to mind. My copy is in anothe office right now.

Regards
Pat
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[loughnane]

Thanks

Chris Loughnane - Product Design

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